This proposal consists of two distinct but inter-related projects. The first project is concerned with the use of multifactorial methods to study temporal trends in malignant melanoma, and to obtain age curves for malignant melanoma that are free of the distortions produced by historical effects. Incidence and mortality data from various population-based registries will be analyzed in order to measure the impact of environments in early and adult life on the temporal evolution of the disease. The second project proposes to test a model for malignant melanoma against epidemiologic data. In order to do this, a multifactorial analysis, as proposed in the first project, is a necessary pre-requisite. This model incorporates the known biologic features of melanoma, such as the B-K mole syndrome, and the known risk factors such as UV-B irradiation. The mode of action of UV-B will be inferred within the context of the model. Finally, the model will be used in conjunction with multifactorial methods to evaluate the impact of a depletion of the ozone layer on melanoma rates.